1，Before 2006/12, are u singapore PR?
2, If you are, this condition should be covered in CPF shield plan, which will intregated into Incomeshield plan also. Claim should be no problem;
3, If not, please go and check your Incomeshield plan contract to see what is the defination of pre-existing condition; Is you situation meet the defination?
4, The main point is whether doctor can approve that you're ok before 1/5/2007 or they can't find any clue you have such kind of pre-existing condition. (But you don't go back and check again, so the claim became difficult.)

Any question, you can sent me an email: jackyfengbin@yahoo.com